Losing Nemo 2 – clownfish swim towards predators as CO2 levels rise

[n2doc]

If you think the stars of Pixar’s Finding Nemo had it rough, spare a thought for the plight of real clownfish. These popular fish may struggle to survive in oceans that are becoming enriched with carbon dioxide. High levels of CO2 dissolved in the water can muddle a clownfish’s sense of smell, preventing it from detecting both shelter and threats.

Philip Munday from James Cook University has shown that at levels of carbon dioxide within what’s predicted for the end of the century, a clownfish’s ability to sense predators is completely shot. Some larvae become literally attracted to the smell of danger and start showing risky behaviour. It’s not surprise that they die 5-9 times more frequently at the mouths of predators.

The conditions that Munday simulated in his experiment aren’t too far away. Thanks to the carbon dioxide that human activities produce, carbon dioxide levels in the atmosphere are predicted to reach 500 parts per million (ppm) by the middle of this century, and between 730-1020 by its end. Much of this gas dissolves in the oceans, making them more acidic. In the past two centuries, the pH value of the world’s oceans has fallen 100 times faster than any time in the past 650,000 years.

The actual fall in pH values seems quite small – just 0.3-0.4 units, barely visible on a litmus test. But this tiny difference can have a big impact on marine life. It depletes the water of ions that corals and shellfish need to build their shells and reefs. But Munday has shown that fish suffer too. Last year, he showed that when carbon dioxide levels in the water go up, baby clownfish lose their ability to find their way home. Contrary to Finding Nemo, young reef fish grow up in the open ocean, far away from their birthplace. They rely on their sense of smell to swim home, but with that sense baffled by CO2, they could end up anywhere.

more

http://blogs.discovermagazine.com/notrocketscience/2010/07/06/losing-nemo-2-clownfish-swim-towards-predators-as-co2-levels-rise/

[Mimosa]

1. So sad...

But we need to know about it.

[CoffeeCat]

2. Oh great...

...now BP killed Nemo.

I can't take the horrible, awful news that emanates from this oil gusher/BP story. It's just
one big heartbreaking catastrophe after another, and BP doesn't give a rat's ass about any of it.
In fact, they probably laugh their asses off about all of it.

edited for spelling

[Auggie]

3. Mercury found in fish from San Francisco water supply: atmospheric deposition?

From coal-fired energy producers in China??? That's one theory...

Link from earlier today: http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=141x37635

Hasn't taken humans long to really fuck up the planet, has it?